The invention relates to a pipe carrying hot gases for an internal-combustion engine which is surrounded with a spacing by a liquid cooled covering and with several brackets arranged at the thin walled pipe and fastening means interacting with the brackets to fix the pipe at the covering. By means of this type of an arrangement, it is prevented that the hot gas comes in direct contact with the liquid-cooled covering, whereby the influx of heat into the coolant is kept low.
An arrangement of this type of a pipe carrying hot gases is known from German Utility Model (DE-GM) 80 13 256. Several flange-type brackets are distributed over the length at each longitudinal side of the thin-walled pipe and rest against a corresponding flange surface of the liquid-cooled covering. The fastening of the pipe takes place by means of screws inserted vertically with respect to the flange face. The high temperatures of the hot gases, which occur during the operation, result in considerable thermal expansion differences between the pipe and the covering, which are compensated only partly by the fastening. Thermal expansions which cannot be compensated result in constraining forces of expansion which result in a stress to the material which cannot be calculated. The effects of the constraining forces of expansion, when added to the stress to the internal-combustion engine caused by the operation, such as vibration and gas pulsation, result in a stressing of the pipe which endangers the operation.
It is therefore the object of the invention to provide a pipe for carrying hot gases for an internal-combustion engine which results in an operationally safe connection between the pipe and the liquid-cooled covering.
According to the invention, this object is achieved by providing an arrangement characterized in that the connection of the pipe and the covering takes place in only one cross-sectional plane, in that at least two brackets are distributed in the cross-sectional plane at the circumference of the pipe, in that each bracket has a fastening arrangement radially interacting with a fastening device, and in that the pipe, in the mounted state, in the area of each bracket, has a radially smaller dimensioning with respect to the covering, which is eliminated after the effect of the fastening devices. After the installation of the pipe into the covering, the wall sections between the brackets are deformed by tensile stress at least in areas on both sides of the cross-sectional plane of the screws. The deformation is in the magnitude of the thermal expansion to be expected at the operating temperature. The deformation of the pipe generated in the cold state, will decline during the heating, in which case the tensile stress is reduced. In the case of this, as it were, programmed thermal expansion of the pipe, a stressing of the material, that cannot be calculated, by means of constraining forces, is avoided. Other developments of the invention are found in the various claims.
The advantages achieved by means of the invention are mainly that the generating of the pipe deformation takes place necessarily with the mounting of the fastening devices, that the fastening devices can be controlled from the outside, that the smaller dimensioning, which results in the deformation of the pipe, can be measured clearly during the mounting and that a low-cost production of the pipe fastening is obtained.